What is the process for determining the total of elements within an array?

Question

What is the process for determining the total of elements within an array?

Imagine you have the following array:

const items = [
  {
    "amount1": "100",
    "amount2": "50",
    "name": "ruud"
  },
  {
    "amount1": "40",
    "amount2": "60",
    "name": "ted"
  }
]

Your goal is to calculate the sum of all amount1 and amount2 properties, resulting in:

[
  {
    "amount1": 140,
    "amount2": 110
  }
]

How would you go about achieving this?

javascript arrays

Answer 1

Answer №1

Utilizing Array.prototype.reduce() in combination with Object.entries() and Array.prototype.forEach():

const items = [{amount1: 100, amount2: 50}, {amount1: 40, amount2: 60}];

const sums = items.reduce((acc, item) => {
  Object.entries(item).forEach(([k, v]) => acc[k] = (acc[k] || 0) + v);
  return acc;
}, {});

console.log(sums);

To eliminate non-numeric properties (while preserving quoted number strings, based on the updated query):

const items = [{amount1: '100', amount2: '50', name: 'Ruud'}, {amount1: '40', amount2: '60', name: 'Ted'}];

const sums = items.reduce((acc, item) => {
  Object.entries(item)
        .filter(([_, v]) => !isNaN(v))
        .forEach(([k, v]) => acc[k] = (acc[k] || 0) + Number(v));
  return acc;
}, {});

console.log(sums);

Answer 2

Utilizing Array.prototype.reduce() in combination with Object.entries() and Array.prototype.forEach():

const items = [{amount1: 100, amount2: 50}, {amount1: 40, amount2: 60}];

const sums = items.reduce((acc, item) => {
  Object.entries(item).forEach(([k, v]) => acc[k] = (acc[k] || 0) + v);
  return acc;
}, {});

console.log(sums);

To eliminate non-numeric properties (while preserving quoted number strings, based on the updated query):

const items = [{amount1: '100', amount2: '50', name: 'Ruud'}, {amount1: '40', amount2: '60', name: 'Ted'}];

const sums = items.reduce((acc, item) => {
  Object.entries(item)
        .filter(([_, v]) => !isNaN(v))
        .forEach(([k, v]) => acc[k] = (acc[k] || 0) + Number(v));
  return acc;
}, {});

console.log(sums);

Answer 3

Answer №2

const numbers = [{num1: 100, num2: 50}, {num1: 40, num2: 60}];
function calculateTotal(data){
 const keys =  Object.keys(data[0])
 let result = {}
 for(key of keys)
   result[key]=data.map(x=>x[key]).reduce((a,b)=>a+b);
return result
  
}

console.log(calculateTotal(numbers))

Answer 4

const numbers = [{num1: 100, num2: 50}, {num1: 40, num2: 60}];
function calculateTotal(data){
 const keys =  Object.keys(data[0])
 let result = {}
 for(key of keys)
   result[key]=data.map(x=>x[key]).reduce((a,b)=>a+b);
return result
  
}

console.log(calculateTotal(numbers))

Answer 5

Answer №3

Here's a quick and efficient solution to tackle this problem.

const data = [{num1:100, num2:50, title:"John"},{num1:40,num2:60,title:"Jane"}]
let total = [{num1:0,num2:0}]
data.forEach(item=>{
  total[0].num1 += item.num1
  total[0].num2 += item.num2
})
console.log(total)

Answer 6

Here's a quick and efficient solution to tackle this problem.

const data = [{num1:100, num2:50, title:"John"},{num1:40,num2:60,title:"Jane"}]
let total = [{num1:0,num2:0}]
data.forEach(item=>{
  total[0].num1 += item.num1
  total[0].num2 += item.num2
})
console.log(total)

Answer 7

Answer №4

Below is an alternative approach that does not rely on Array.prototype.reduce(). This solution accommodates scenarios where there are properties in the array items that are not strictly "numbers".

 const elements = [{quantity: 10, weight: 5, product: 'Apple'}, {quantity: 4, weight: 6, product: 'Banana'}];
 var finalResult = {};

 elements.forEach(function(element){
    for(var key in element){
        if(typeof element[key] === "number"){
           finalResult[key] = finalResult[key] ? finalResult[key] + element[key] : element[key];                 
        }                
     }
 });
 finalResult = [finalResult];
 console.log(finalResult);

Answer 8

Below is an alternative approach that does not rely on Array.prototype.reduce(). This solution accommodates scenarios where there are properties in the array items that are not strictly "numbers".

 const elements = [{quantity: 10, weight: 5, product: 'Apple'}, {quantity: 4, weight: 6, product: 'Banana'}];
 var finalResult = {};

 elements.forEach(function(element){
    for(var key in element){
        if(typeof element[key] === "number"){
           finalResult[key] = finalResult[key] ? finalResult[key] + element[key] : element[key];                 
        }                
     }
 });
 finalResult = [finalResult];
 console.log(finalResult);

Answer 9

Answer №5

If you are looking to consolidate the numeric values in an array of objects, one effective approach is to utilize the reduce() method.

To implement this solution:
Apply the reduce() method on the target array, which we've referred to as items.
Define the accumulator (ac) as an empty object - {}.
Within each iteration over the objects, use a for..in loop to cycle through all keys within the object.
Verify whether the typeof value for the current key is a number; if so, include it in the accumulation.

const items = [{amount1:100, amount2:50, name:"ruud"}, {amount1:40,amount2:60,name:"ted"}]

let res = [items.reduce((ac,x) => {
  for(let key in x){
    if(typeof x[key] === "number"){
      if(!ac[key]) ac[key] = 0;
      ac[key] += x[key]
    }
  }
  return ac;

},{})]
console.log(res)

Answer 10

If you are looking to consolidate the numeric values in an array of objects, one effective approach is to utilize the reduce() method.

To implement this solution:
Apply the reduce() method on the target array, which we've referred to as items.
Define the accumulator (ac) as an empty object - {}.
Within each iteration over the objects, use a for..in loop to cycle through all keys within the object.
Verify whether the typeof value for the current key is a number; if so, include it in the accumulation.

const items = [{amount1:100, amount2:50, name:"ruud"}, {amount1:40,amount2:60,name:"ted"}]

let res = [items.reduce((ac,x) => {
  for(let key in x){
    if(typeof x[key] === "number"){
      if(!ac[key]) ac[key] = 0;
      ac[key] += x[key]
    }
  }
  return ac;

},{})]
console.log(res)

Answer 11

Answer №6

reduce() is definitely the best approach, but a more elegant way to handle only specific keys is by using the expected result as the accumulator and iterating over its keys:

const items = [
  { amount1: "100", amount2: "50", name: "ruud", foo: "unrelated" },
  { amount1: "40", amount2: "60", name: "ted", foo: "0" }
];

const result = items.reduce((acc, item) => {
  for (let key in acc) { // loop through the keys of the accumulator
    acc[key] += isNaN(item[key]) ? 0 : +item[key];
  }
  return acc;
}, { // defining the expected format here
  amount1: 0,
  amount2: 0
});

console.log(result);

Answer 12

reduce() is definitely the best approach, but a more elegant way to handle only specific keys is by using the expected result as the accumulator and iterating over its keys:

const items = [
  { amount1: "100", amount2: "50", name: "ruud", foo: "unrelated" },
  { amount1: "40", amount2: "60", name: "ted", foo: "0" }
];

const result = items.reduce((acc, item) => {
  for (let key in acc) { // loop through the keys of the accumulator
    acc[key] += isNaN(item[key]) ? 0 : +item[key];
  }
  return acc;
}, { // defining the expected format here
  amount1: 0,
  amount2: 0
});

console.log(result);

What is the process for determining the total of elements within an array?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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